Overrunning clutches, especially those having cylindrical rollers that serve as the wedging elements, generally include a cage structure and a plurality of roller energizing springs. Preferably, the cage, rollers and springs are shipped as a unitary assembly, so as to be easily installed between a pair of clutch races. The rollers are generally the heaviest part of the assembly, and the most difficult to retain prior to installation. This is known as the shipping retention, and refers to either shipping or installation handling of the clutch. A common means of shipping retention may be seen in the U.S. Pat. No. 3,760,914 to Gelbrich. As there disclosed, rollers 3 are retained to a cage 4 by being pushed by the energizing spring 6 against specially configured cross bars 9. However, the strength of the shipping retention force that can be provided by an energizing spring is very limited. An energizing spring need not be particularly strong in order to energize the roller during operation of the clutch. In fact, if the spring were made stronger, in order to provide more shipping retention force on the roller, then the spring would bias the roller too strongly between the confronting surfaces of the races during clutch operation, causing an unacceptable level of friction. Therefore, such clutches must be handled very carefully during shipping and handling to avoid shaking the rollers out.
There are examples of clutches providing a stronger retention of the rollers to the cage. One example may be seen in the U.S. Pat. No. 4,415,072 to Shoji et al. There, the ends of the rollers 11 have hollowed out portions 11A. Projections 22A stamped into the cage side rails 22 extend into the hollowed out portions 11A, thereby retaining the rollers 11 to the clutch assembly more strongly than would conventional spring force. However, the rollers 11 are not particularly closely radially confined, and can rattle relative to the cage. More importantly, the operational roller travel allowed is inevitably limited to less than the diameter of the roller 11. This limitation is unacceptable in most clutch applications. A similar structure may be found in the U.S. Pat. No. 3,942,616 to Elmore. There, tabs 26 bent off of the cage side rail 16 extend into hollowed out portions 76 in the ends of rollers 80, also retaining the rollers to the cage. However, the operational roller travel is similarly limited. Because of this limitation on roller travel, only those designs using the spring force for roller retention have found wide spread production use, in spite of the weakness of the shipping retention force available.